<?php
$arr['Monday']['food'] = ['rice'];
$arr['Monday']['fruits'] = ['apple', 'grape', 'peach'];
$arr['Monday']['vegetables'] = ['potatoes', 'carrot', 'onion', 'fish'];
$arr['Tuesday']['food'] = ['noodles'];
$arr['Tuesday']['fruits'] = ['orange', 'watermelon', 'mango', 'cherry'];
$arr['Tuesday']['vegetables'] = ['bean', 'tomato', 'egg', 'chicken'];
print_r( $arr );